There has been a trend over the past several years to provide argicultural combines of greater threshing capacity. While the size of combines has been increased over earlier designs, there appear to be practical limits to physical increases in size of the crop cutting header portion of the combines.
The productivity of large capacity combines may be increased by operating at a higher ground speed, which requires a higher cutter speed. In the case of a reciprocating sickle type cutter, the inertia related forces in the cutter mechanism increase with the square of the frequency of reciprocation. The present invention is directed to providing a cutting mechanism which operates at high speed without imposing unduly high forces on its drive mechanism. One concurrent development in this direction is the resonant cutting mechanism shown in a copending U.S. patent application Ser. No. 186,571 by Larry F. Stikeleather and Tony L. Kaminski filed Sept. 12, 1980 for Resonant Sickle Drive wherein a torsion bar is connected to the output lever of the wobble drive for the sickle. A second concurrent development aimed at somewhat high sickle operating speeds is the resonant sickle drive shown in copending U.S. patent application Ser. No. 220,502 by Paul T. Shupert filed Dec. 29, 1980 for Resonant Sickle Drive with Spring Means at Opposite Ends of the Sickle.
Prior art devices using resilient spring devices for cushioning or for storing and releasing energy during reciprocation of a cutting device include U.S. Pat. Nos. 273,341; 2,109,085; 3,538,690 and 3,624,990.